Super Freak, Super Freak

So we now turn our attention back to the Arturia MicroFreak that I had picked up on a whim. After a bit more investigation I was able to determine a few things.

First off, thanks to the thermal camera I picked up, I was able to narrow down the failure of the 6v +/- supply to the regulator itself, and not any of the chips it powers.

Secondly, I was able to figure out that it's actually just a 6v supply, not a 6-7v supply. I misinterpreted a page on the datasheet regarding how the positive and negative voltages are calculated across the sense resistor bridge.

Thirdly, I discovered that the supply actually only powers three chips in the VCO and VCF circuits, not the audio output. The latter is actually driven by a 1.8v linear regulator, which is apparently sufficient to drive low-impedance headphones. Go figure.

Anyway, the full repair is documented here:

And I'm glad to report that the fix worked great. The synth has actually been performing solidly for a few weeks now and shows no signs of failing again, though who knows how long that'll last. Hopefully forever.

Also the rose bush is in full bloom

Which is nice.

I See A Red Door

This is the door to my car hole.

And let's just say it's seen some shit. Part of the problem is that it's just a basic wood door exposed to the elements, with no awning or overhang to keep the rain off of it. Part of the problem is that it was just never installed correctly from the get-go.

Part of the problem is that it's been literally chewed to pieces and (barely) cobbled back together with whatever bodge was closest at hand.

The frame is in no better shape of course, having rotted out at the top and definitely at the bottom.

On both sides, of course.

So a simple slab-swap isn't going to do here. Instead, we'll need to get much more invasive.

This is a long one, so click through to read more.

Grease Thy Hammer

This is my Boschhammer.

It's a rotary hammer, which is basically a hammer drill that put its big boy pants on. What I didn't realize about it, because I probably never read the manual, is that you're supposed to grease the chisels/bits that you insert into the chuck. This is a rather peculiar act for someone who might be more used to standard drills with Jacobs-style chucks, but the SDS+ chuck is a peculiar beast.

The lubrication of the bit against the chuck isn't really the goal here, though it's a nice-to-have element given that the bit is expected to move within the chuck when in use; unlike a hammer drill the hammering action is transmitted directly to the base of the bit, rather than hammering on the whole chuck itself. We'll see how that works in a bit.

The real goal of greasing the chisels is to keep the inner workings of the chuck fully lubricated, as it does have a number of moving parts that are frequently exposed to dust and grit. If the lubrication runs out or cakes up and gets sticky, the hammering action can become sluggish and you may have to apply excessive force to the drill to get it to hammer properly. At worst, the anvil can seize within the chuck, rendering the hammering action completely inoperative.

So with that in mind, let's pull this chuck apart to give it a nice grease-bath.

First up, we pull off the rubber end cap. This just seals the dust out of the chuck (as well as can be expected) and fairly easily pries off the end of the chuck.

Next up, we spend 30 minutes stabbing our fingers while trying to pry off not one but two retaining rings. Ugh. The topmost ring holds a washer in place, while the one below it holds the bit release collar.

The collar holds basically 90% of the chuck together. With it removed we can pull out the ball bearing that retains the bit, as well as its spring and washer, and also slip out the four pins that hold the bit holder into the base of the chuck.

With the pins removed, the bit holder slides out, and the anvil should come with it. This is what gets the bulk of the grease every time you slip in a well greased bit.

The rest of the chuck doesn't disassemble from this side, and shouldn't need a lot of attention. However, we can pull the nose of the drill off by removing 4 T30 screws with an extra long bit.

And then we can peer inside to ensure that the grease here is still present in copious quantities.

The shaft on the upper right is what transmits the drilling action to the chuck, while the hollow sleeve on the left is what holds the chuck itself on the other side, and the hammering action is transmitted through to the anvil through the hollow center.

And all that mates up with this pile of greasy mechanics.

I moved a bit of the grease around from where it had collected in nonfunctional places, but I didn't see any need to mess with this stuff any further.

The rest of the chuck, though, was going to get a nice coating of fresh grease. This is probably not the correct grease to use, except that it's the grease I happened to have on hand at the time so it was absolutely the correct grease to use.

Anyway, the chuck just reassembles in the reverse order of disassembly, with the appropriate care taken to grease things up along the way, and then it's all back together ready to poke holes in impossibly hard materials again.

Though ironically the reason I thought to service this was actually because I'm ordering a mortar mixing paddle that fits into an SDS+ rotary hammer (in rotary mode, not hammer mode). I figured it made sense to get that rather than burning out my regular drill trying to use one with it, or spending $50 to get a standalone mortar mixer that I'd only use once or twice ever, and which would probably burn itself out immediately because it's a $50 mortar mixer.

But that mortar mixing will be a story for a future blog post.

Stomp Around

So my Arturia Microfreak synthesizer is up and running, which is a story I will recount in a future blog post. I've been enjoying it a lot, but one thing that the Microfreak is lacking is any built-in effects. Usually for almost any instrument you want at least a certain baseline collection of effects, starting with reverb and delay. For a synthesizer in particular, especially a non-stereo synth like the Microfreak, a stereo chorus is really helpful for opening up the sound. From there, other effects are icing on the cake.

Now I could get 3 different effects pedals to chain together to give me my reverb, delay and chorus, but the setup I have with the Microfreak is very compact and I'd like to keep things that way. So, enter the Zoom MS-50G multi-effects pedal.

This unit is basically an entire pedalboard-in-a-box, where you can digitally chain together 6 effects of your choosing from a broad library of built-in effects, or even load it up with custom effects via USB, which is pretty cool. This particular model is mono-in and stereo-out, which is perfect for my Microfreak.

Now I could have gone with a different model that has both stereo in and out, or even the updated version of this model, but from the research I've done, this specific one is, curiously, the most compatible with sideloading homebrew effects... And it's also cheaper because I picked it up used.

However it's only barely used. The seller said that they bought it and never used it, and I'd believe it. There really wasn't a single scratch on it, and only a tiny bit of dirt stuck to the little rubber pad on the underside that keeps the pedal from sliding across the stage when you step on it (like most pedals it's technically designed for guitars rather than keyboards).

Really the only complaint I can come up with is that there's a tiny bit of background noise when I'm running it off USB, but the noise gets drowned out completely once I start playing so I'm not particularly bothered by it.

In all it makes for a delightfully compact and sweet sounding setup.

Seeing The Unseen

I picked up an IR camera recently, now that they've sunk to the low-low price of "it's practically free". I bought it specifically for a project I'll cover on a future post, but for a test run I decided to go around my house and look for energy leaks.

Like this energy leak, for instance.

I'm pretty sure that the insulation contractor who worked on the addition on my house ran out of fiberglass batts when they got to this end and just decided that they didn't care enough to go get more.

There's also this gap in the middle of the same ceiling, which seems a bit peculiar.

I'm not too concerned about it though, partly because it's a pretty small area that isn't actually leaking all that much heat, and partly because there's no access to this space without tearing off the roof and/or ceiling, and I'm sure not gonna deal with that.

Speaking of roofs and/or ceilings, it's rather amusing to see the shadow of the solar panel through the roof of my car hole.

I really need to insulate in here, it gets oppressively hot during the summer to the point where I can't go out and get any work done, and that's really dragged down my hobby productivity. Interestingly I had assumed that the walls would also be letting in gobs of heat, but it appears not to be the case: the wall in the bottom of this picture is in direct sunlight and was something like 50c on the outside, but with nothing but a stud bay air gap and some drywall on the inside, there's really not much heat making it through compared with what's blasting through the roof.

I'm still going to insulate both, though.

It Really Ties The Room Together

Today I went in search of a door. I did not find it. I thought I would get one at Lowes, but apparently whoever is running Lowes doesn't understand that people do house work on, say, the weekends, and so it's closed on Sundays.

Not to be deterred, I decided to check the Habitat ReStore to see if any discount doors might be available there. There were not. There were, however, rugs.

Like this rug.

For context, this is what was there before.

This was an extra bath mat that I got probably as a "buy the 2-pack, it's cheaper than buying only one" combo a while back, and while it felt nice under-toe, it really wasn't quite the right size for the space.

The red monstrosity is my towel, which I drape over a foot stool to dry. As one does.

Speaking of things being moist, rugs don't just arrive in your home nice and flat. Rather, they usually come rather curly on the ends from being rolled up for shipping. While you might be tempted to use an iron to steam them into relaxation, this is not really the right tool for the job.

Unfortunately the temperature that an iron needs to be at to generate steam is above the temperature needed to melt whatever acrylic-scotchbrite blend that cheap rugs like these are made of. You can try hovering the iron above the surface, but it's really better to use an actual steamer for the job.

Like this one, for instance. I bought it originally to clean the grout on my tile floors (covered in a blog post a while back) and it's nice to find another use for it.

Anyway, the steaming went well and the rug flattened out nicely, and with the aid of a little carpet tape it's now securely tucked into place.

And worry not: the entoweled footstool has regained its rightful position.

Getting Freaky

So I was flipping through the seedier parts of eBay the other day, and happened upon a listing for a "broken" Arturia Microfreak synthesizer. I tossed a lowball bid on a lark and, wouldn't you know it, scored it for less than $100 including shipping. It usually sells new for $350, for comparison.

The stated problem? It was boot-looping and refused to flash. So I power it on and wouldn't you know it, it's stuck on this screen.

So that's a good sign. I've been getting pretty bored of buying "broken" audio equipment only to find that it was actually working perfectly.

Anyway, I figured maybe I could get a quick "if your microfreak is boot looping, just do this, dummies" YouTube video out of using one of the magic-key-combo rescue procedures to reflash the device, but just as a quick test I plugged it into my MacBook Air to verify that it would, indeed, not flash using the normal procedure.

Oh.

Yup. Flashed just fine, no special konami-code needed.

But the story doesn't end here. There's no onboard speaker on this model, so I plugged it into my mixer to give it a test run and... nothing, no sound. Well, not exactly nothing, more like "horrible ground loop buzzing". So I swapped out the included power supply for a USB cable (it can run off of either) plugged into the USB outlet on my power strip, and got less ground loop buzzing this time, but still no usable audio. So for try number three I grabbed a USB wall wart and plugged it into that one and finally cleared up the ground loop buzzing, but still got no love in the form of producing actual audio out.

Ok, well, that's not great. Now I'm starting to suspect that something really is wrong with this device.

So I pop it open and take a poke around. The main 3.3v power supply is doing just fine, as evidenced by the display and lights and so on all responding normally, but it's nice to confirm that directly.

Using only 3.3v to drive the audio output wouldn't result in much volume though, so poking around a bit further lead me to find a split-supply boost converter in the middle of the board. Checking the sense resistor bridge, it seemed to be configured to deliver around 6 to 7 volts plus and minus (I didn't check which was which, but I'm assuming they configured it for +7 and -6 so that it would be centered on +0.5v so that there wouldn't be any DC offset for a 0-1v audio signal).

On the backside of the board, these three test points are connected to the positive, ground and negative supply rails generated by the boost converter.

So let's check one of them.

Ok, that's definitely not 6-7 volts. How's the other one look?

Ah, right. Yeah, that's not at all the voltage it should be.

I did a bit more probing and the regulator is oscillating at around 440kHz, which seemed like a reasonable value, so the regulator chip itself likely isn't to blame. However, when I powered down the unit and measured the resistance across the test points, one of them read a reasonably high value, but the other, the one showing only 1/4 of a volt, measured 11ohms. That is suspiciously low.

So likely what happened is that the output amplifier got a few too many dancing pixies rammed back up its arsehole and lost all its magic smoke. Reading up online, this is apparently quite a common failure with this synth when people accidentally forget to turn off the 48v phantom power on their mixer and plug this in, and I guess Arturia didn't think to include any protection circuitry. (And no, I did not leave the 48v phantom power on MY mixer turned on)

Anyway, I didn't feel like chasing this down any further right then, so I sent an email off to Arturia tech support to inquire about obtaining a replacement board, and we'll see where that goes.

To be continued...